Thermochemical study of 2,5-dimethyl-3-furancarboxylic acid, 4,5-dimethyl-2-furaldehyde, and 3-acetyl-2,5-dimethylfuran

The standard (p° = 0.1 MPa) molar enthalpies of formation, in the gaseous state, at T = 298.15 K, for 2,5-dimethyl-3-furancarboxylic acid, 3-acetyl-2,5-dimethylfuran, and 4,5-dimethyl-2-furaldehyde were derived from the values of the standard molar enthalpies of formation, in the condensed phase, and the standard molar enthalpies of phase transition from the condensed to the gaseous state. The values of the standard molar enthalpies of formation of the compounds in the condensed phases were calculated from the measurements of the standard massic energies of combustion obtained by static bomb combustion calorimetry. The enthalpies of vaporization/sublimation were measured by Calvet high temperature microcalorimetry. For 2,5-dimethyl-3-furancarboxylic acid the standard enthalpy of sublimation was also calculated, by the application of the Clausius–Clapeyron equation, to the temperature dependence of the vapor pressures measured by the Knudsen effusion technique.Compound-ΔfHm∘(cr,l)/(kJ·mol-1)Δcr,lgHm∘(T=298.15K)/kJ·mol-1CalvetKnudsen2,5-Dimethyl-3-furancarboxylic acid (cr)600.4 ± 1.599.0 ± 1.7100.9 ± 0.53-Acetyl-2,5-dimethylfuran (l)352.1 ± 1.857.5 ± 1.54,5-Dimethyl-2-furaldehyde (l)294.5 ± 1.757.7 ± 0.6Full-size tableTable optionsView in workspaceDownload as CSV